Common bugs curable regularly (5)
I believe the answer is:
usual
'common' is the definition.
(associated in meaning)
'bugs curable regularly' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'bugs'+'curable'='bugscurable'
The alternate letters of 'bugscurable' are 'USUAL'.
(Other definitions for usual that I've seen before include "Typically done" , "Normal, habitual" , "Expected" , "Common, normal" , "Drink repeatedly taken" .)